Conventionally, among data processing apparatuses such as a printer (also referred to as “image forming apparatus”) that is equipped with a large capacity hard disk, an apparatus is known which allocates a plurality of memory boxes to individuals by dividing a storage area on a hard disk to provide each of the storage areas for each individual. In this kind of printer, an image received from a host computer can be stored in a specified area (memory box) and the image stored in the memory box can then be printed.
Since there is also a lot of image data normally resident in the memory boxes in addition to the image data that is temporarily stored there for printing, unless image data inside the memory boxes is erased, the hard disk will run out of free storage space (the hard disk will become full) and it will not be possible to newly store image data on the hard disk.
In particular, in a POD (print on demand) system that provides a print output service via the Internet, image data is frequently introduced into memory boxes. Since printing that utilizes this kind of POD system is mainly large quantity printing, the memory boxes soon become full and it is necessary to wait for a state in which it is okay to erase image data within the memory boxes before erasing the image data in the memory boxes.
In view of the foregoing, there has been proposed configuration in which image data recorded in a memory box of a printer is transferred to an external computer, erase the image data corresponding to the transferred image data from the memory box, and in accordance with the amount of free space in the memory box, return the image data that was transferred to the external computer to the memory box (for example, see Japanese Laid-Open Patent Publication (Kokai) No. H11-234493). According to this configuration, even when a memory box provided in the printer is full, it is possible to store image data that has been transferred from an external computer in the memory box.
However, there is the following problem with the above described Japanese Laid-Open Patent Publication (Kokai) No. H11-234493.
When performing a predetermined operation, for example, print output operation on image data stored in a memory box, although when the image data is present inside the memory box, the operation can be carried out immediately, in the case of image data that has been transferred to an external computer, since the image data is erased from the memory box, it is necessary to transmit the image data back to the memory box again for printing. At this time, since it is necessary for the user to check the free space in the memory box and, based on the result, to transmit the image data back to the memory box from the external computer, it is not possible to immediately perform an operation for image data that has been sent to the external computer.
Further, a printer that does not include a large capacity hard disk cannot even have a memory box function.
It is an object of the present invention to provide a data processing apparatus and control method thereof that can flexibly deal with various needs of a user while effectively utilizing a memory unit thereof that can store a plurality of data, as well as a program.
Another object of the present invention is to provide an image processing apparatus and a control method thereof, and a display control apparatus and a control method thereof that enable a user to use a memory box without being concerned about the capacity of a hard disk when using the hard disk as an area of the memory box, and furthermore, that also realize a memory box function in an apparatus which is not equipped with a large capacity hard disk, as well as a control program.